Add read watchpoints (fixes #69)
Add read watchpoints (fixes #69)

mgba-emu/mgba,askotx/mgba,mgba-emu/mgba,fr500/mgba,MerryMage/mgba,Iniquitatis/mgba,iracigt/mgba,jeremyherbert/mgba,mgba-emu/mgba,iracigt/mgba,libretro/mgba,Iniquitatis/mgba,bentley/mgba,fr500/mgba,AdmiralCurtiss/mgba,libretro/mgba,Anty-Lemon/mgba,Anty-Lemon/mgba,askotx/mgba,askotx/mgba,Touched/mgba,MerryMage/mgba,Iniquitatis/mgba,sergiobenrocha2/mgba,nattthebear/mgba,Touched/mgba,fr500/mgba,MerryMage/mgba,cassos/mgba,zerofalcon/mgba,zerofalcon/mgba,cassos/mgba,Touched/mgba,cassos/mgba,jeremyherbert/mgba,sergiobenrocha2/mgba,matthewbauer/mgba,jeremyherbert/mgba,bentley/mgba,jeremyherbert/mgba,Anty-Lemon/mgba,mgba-emu/mgba,iracigt/mgba,Iniquitatis/mgba,Anty-Lemon/mgba,iracigt/mgba,libretro/mgba,sergiobenrocha2/mgba,libretro/mgba,sergiobenrocha2/mgba,fr500/mgba,zerofalcon/mgba,askotx/mgba,sergiobenrocha2/mgba,AdmiralCurtiss/mgba,AdmiralCurtiss/mgba,libretro/mgba,matthewbauer/mgba,nattthebear/mgba